To get the most from your glue pump, take a look at the suction side...

Your glue pressure delivery is inconsistent and you can't work out why. You've checked the valve, the regulator, even the pump and everything is working correctly.

Did you ever consider the suction side of the pump? Perhaps the line is 10m (30ft) long or has two 90-degree elbows in it? Worse yet, maybe someone inadvertently installed a natural rubber line instead of the proper wire-reinforced PVC material.

When natural rubbers are used, the ingredients in modern adhesives can cause degradation of the hose and black particles to break off and clog heads and nozzles. However, the length of the suction line, the number of 90-degree bends in it and the height of the pump all contribute to resistance in the suction line that can cause cavitations and starvation on the high side of the pump. Normally, the pump should be no more than 1 meter (3.5 ft) higher than the pail or drum. The suction hose should be kept shorter than 3m (10ft) with a maximum of one elbow to connect to the feed tube. Using a reinforced material like the Valco® 755XX522 hose will prevent it from collapsing and cutting off flow to the pump.

Remember, the condition of the suction side of your liquid adhesive pumping systems is just as important as the rest of the glue system, so remember to consider this if you want to get the most for your buck.